Hackers turned 150 French supermarkets' fridges into 50°C defrost ovens

On Sunday night, hackers broke into the refrigeration systems of about 150 Intermarché supermarkets across France, setting the cooling units to defrost and sending temperatures to 50°C for roughly six hours. The result: stores had to throw out meat, frozen goods, and vegetables, according to a spokesman for Groupement Mousquetaires, Intermarché's parent company, in a statement to Bloomberg.

The attack didn't just disrupt a single store - it hit hundreds of locations simultaneously, turning a routine cyber intrusion into a physical supply chain crisis. For a supermarket chain, refrigeration is the backbone of fresh food operations; when it fails, the losses are immediate and irreversible. The 50°C heat essentially cooked the inventory, making it unsellable and forcing staff to discard products that had been destined for shelves. The scale of the waste is staggering: imagine the contents of an entire frozen food aisle, from ice cream to frozen peas, all rendered unusable in a matter of hours.

This incident is part of a broader pattern of cyberattacks targeting critical infrastructure. While most headlines focus on ransomware hitting hospitals or pipelines, retail refrigeration systems are increasingly attractive targets because they are often connected to the internet for monitoring and efficiency, yet rarely secured with the same rigor as corporate IT networks. A single vulnerability can give attackers remote control over temperature settings, as seen here. The attackers didn't steal data or demand a ransom - they simply flipped a switch, and the physical world responded.

For Intermarché and its parent Groupement Mousquetaires, the financial impact goes beyond the cost of spoiled inventory. There are cleanup costs, lost sales during the outage, potential insurance claims, and reputational damage as customers question whether their local store can keep food safe. The company has not disclosed the total value of the losses, but for a chain operating hundreds of stores, the figure could run into millions of euros. Insurance policies for business interruption may cover some of the damage, but cyberattacks on operational technology are often excluded from standard policies, leaving retailers exposed.

The attack also highlights a growing operational risk for retailers: the convergence of IT and OT (operational technology). In the past, refrigeration systems were isolated, but modern 'smart' stores connect them to central management platforms for energy savings and remote diagnostics. That connectivity creates a larger attack surface, and this incident shows that a cyber intrusion can have physical consequences - in this case, ruined food and empty shelves. For security teams, the challenge is that OT systems are often managed by facilities engineers, not IT, and may run on legacy protocols that are difficult to patch.

Regulators are paying attention. The European Union's NIS2 Directive, which came into force in 2024, expands cybersecurity requirements to more sectors, including food distribution. While the directive focuses on reporting and risk management, incidents like this one are likely to accelerate calls for stricter security standards on operational technology in retail. For now, the onus is on companies to segment networks, monitor for anomalies, and ensure that critical systems like refrigeration have manual overrides. The fact that the attack happened on a Sunday night - a time when staffing is often thin - suggests that attackers are deliberately targeting moments when response capabilities are weakest.

For other retailers and any business that relies on temperature-controlled supply chains, the lesson is clear: cyberattacks are no longer just about data breaches. They can directly disrupt physical operations, destroy inventory, and erode customer trust. The Intermarché incident is a reminder that the 'smart' infrastructure that makes businesses efficient also makes them vulnerable - and that a hacker's ability to flip a switch can have very real, very perishable consequences. As supermarkets and logistics providers rush to digitize their cold chains, they must also invest in the security that keeps those chains from becoming attack vectors.